MIL-HDBK-217

MIL-HDBK-217 is a US Department of Defense standard for the reliability prediction of electronic components and provides two reliability prediction methods:

• The Parts Count Method. This is a simpler approach for use during the early design phase and requires less information to be entered, for example quality, quantity and environment.
• The Part Stress Method. This is more complex and requires detailed information on temperature conditions and electrical stress. The part stress method is used when the actual hardware and circuits are being designed.

The Reliability Workbench Prediction Module supports both of these methods to enable you to choose the level of detail you need.

Following this you add accurate data to each component in your system or sub-system. RWB Prediction will then calculate your failure rates automatically.

The screen shot below shows the MIL-217 dialog for setting the parameters of a capacitor:

How do I build a MIL-217 Model?

To build a MIL-217 model you simply define your systems, sub-systems and components in the Prediction tree.

Following this you add accurate data to each component in your system or sub-system. RWB Prediction will then calculate your failure rates automatically.

The screen shot below shows the MIL-217 dialog for setting the parameters of a capacitor:

RIAC 217Plus

The 217 Plus prediction module incorporates the component failure rate prediction models developed by the RIAC (Reliability Information Analysis Center).

The 217 Plus standard considers:

• Quantities
• Adjustment Factors
• Year of Manufacture
• Duty Cycle
• Cycling Rate
• Ambient Temperatures - Operational and Non-operational
• And other part specific variables

Telcordia SR-332

Telcordia SR-332 was originally the Bell Laboratories Bellcore standard for the reliability prediction of commercial electronic components.

What's in Telecordia SR-332?

The Telcordia Standard allows reliability predictions to be performed using three methods:

• Method I provides predictions based on a Parts Count procedure.
• Method II provides predictions based on combining laboratory test data with Parts Count data.
• Method III provides predictions based on combining field tracking data with Parts Count data.

All three methods are handled by the Reliability Workbench Prediction Module.

What can Telecordia do?

The Telcordia SR-332 Standard also provides models for predicting the failure rates of units and devices during the first year of operation.

The failure rate during this wear-in phase is expressed as a multiplying factor operating on the predicted steady-state failure rate. This First Year Multiplier (FYM) is influenced by burn-in times and temperatures. The Prediction Module automatically calculates the First Year Multiplier based on specified system, unit and device burn-in times and temperatures.

The Overview of the Prediction Module page contains a description of the features available in Reliability Workbench for building a Telcordia SR-332 model.

The screen shot below shows the Telcordia dialog for setting the Method II laboratory data:

NSWC-98

NSWC Standard 98/LE1 (Handbook of Reliability Prediction Procedures for Mechanical Equipment) is the US Naval Surface Warfare Center standard for the reliability prediction of mechanical components.

What's in NSWC-98?

NSWC-98 uses a series of models for various categories of mechanical components to predict failure rates which are affected by temperature, stresses, flow rates and various other parameters. The categories of mechanical equipment covered by the Prediction Module are:

• Seals and Gaskets
• Springs
• Solenoids
• Valve Assemblies
• Bearings
• Gears and Splines
• Actuators
• Pumps
• Filters
• Brakes and Clutches
• Compressors
• Electric Motors
• Threaded Fasteners
• Mechanical Couplings
• Slider-Crank Mechanisms

Modeling sub-systems in NSWC

Many of the categories of mechanical equipment are in fact composed of a collection of sub-components which must be modeled by the user. Typical collections include

• Valve Assemblies - poppet/sliding action assembly, seals, springs, solenoids, housing
• Pumps - shafts, seals, bearings, casing, fluid driver
• Brakes & Clutches - actuators, bearings, friction materials, seals, springs
• Couplings - gears, seals, housing
• Slider Crank - bearings, rods/shafts, seals/gaskets, actuators
• Electric Motors - bearings, motor windings, brushes, armature shaft, housing, gears

The user should be familiar with the equipment and the Handbook so that the correct type and number of sub-components can be included in the model.

The Overview of the Prediction Module page contains a description of the features available in Reliability Workbench for building a NSWC-98 model.

IEC 62380

The IEC 62380 standard predicts failure rates for electronic equipment based on the reliability data handbook UTE C 80-810 published by UTE (Union Technique de l'Electricite).

The IEC TR 62380 reliability prediction method considers the effects of phased mission profiles on operating and non-operating components.

This method also accounts for the effects of thermal cycling on the component failure rate due to variations in the ambient temperature and component switch on and off.

IEC TR 62380 also predicts life expectancy for components where applicable.

The Overview of the Prediction Module page contains a description of the features available in Reliability Workbench for building a IEC TR 62380 model.

GJB/Z 299B

GJB uses the part stress method to predict component failure rates. The standard is fully implemented, including the hybrid component. The standard takes into account the effects of environment, quality, electrical and thermal stress on the component failure rate.

The Overview of the Prediction Module page contains a description of the features available in Reliability Workbench for building a GJB/Z 299B model.